Efficient Networks Siemens Sinamics S120 - Manual (Page 336)

Safety Integrated basic functions
9.9 Application examples
Drive Functions
336
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
● The "Safe Torque Off" safety function, which is integrated in the drive, complies with
category 3 to EN 954-1 and SIL 2 to IEC 61508. The non-safe message "Safe Torque Off
active" is sufficient.
● Safety combinations for emergency stop and protective door monitoring comply with
category 4 (instantaneous enable circuits).
● The electric circuits for emergency stop and protective door monitoring are monitored for
cross-circuits on two channels.
● Switches S4, S5, and S6 are positively-opening position switches corresponding to EN
1088.
● Being a higher-level circuit with contacts, the "Safe Stop 1 (SS1)" function also works if
the PLC malfunctions or fails.
● I/O communication via the digital interface between the drive and PLC can also be
replaced by non-safe standard communication (e.g. PROFIBUS).
● This application example is based on the basic functions "Safe Torque Off" (STO) and
"Safe Stop 1" (SS1).
The speed ramps and speed thresholds are monitored in non-safe mode.
Note
In order to implement the Emergency Stop function (stopping in an emergency -
emergency stop) it is not absolutely necessary to electrically isolate the drive converter
from the line supply using electromechanical switching devices according to EN 60204-1
(1998) and IEC60204-1 (2005). When work is carried-out on the motor or drive converter,
the voltage must be disconnected via a main circuit-breaker (that can be locked-out).
Other Standards (e.g. NFPA79-2002 / USA) specify additional requirements regarding
the EMERGENCY STOP function. For the EMERGENCY SWITCHING-OFF function
(switching-off in an emergency) according to EN 60204-1 (1998) and IEC 60204-1
(2005), the supply voltage to the equipment must be disconnected through an
electromechanical switching device. The risk analysis to be carried-out by the machinery
construction OEM must determine which emergency functions (emergency operations)
are actually required for a specific application.
Behavior for Emergency Stop
An emergency stop is triggered by the S3 button ("Emergency stop"). The drive is brought to
a standstill in accordance with stop category 1 of EN 60204-1.
● Open the safe enable contacts of the safety combination A1. This activates the "Safe
Stop 1" drive function on two channels via terminal X122.2 (DI 1) on the Control Unit and
terminals X21.3 (EP +24 V) and X21.4 (EP M) on the Motor Module. "Safe Torque Off" is
selected after the set SS1 delay time (p9852, p9652) has elapsed. When all the grouped
drives have reached the "Safe Torque Off active" status, this is signaled back via terminal
X122.10 (DO 10: STO group active).
● The confirmation from the safety combination and the drive is monitored in the PLC to
ensure that it is plausible.